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APPARATUS, METHODS AND SYSTEMS FOR ROUTING INFORMATION FROM A
PACKET-SWITCHED NETWORK TO A MOBILE DEVICE COMMUNICATING WITH A WIRELESS
TELECOMMUNICATIONS NETWORK

Abstract

Apparatus, methods and systems for routing information from a
packet-switched network to a mobile device communicating with a wireless
telecommunications network, wherein a call request for a mobile device is
received from the packet-switched network at a first node of the wireless
telecommunications network; a determination is made of the serving node
of the wireless telecommunications network in communication with the
mobile device and whether the serving node is coupled to the
packet-switched network; and the call request is redirected to the
serving node in response to an affirmative indication that the serving
node is coupled to the packet-switched network. Alternatively, in
response to a negative indication that the serving node is coupled to the
packet-switched network, the call request is routed from the first node
to the serving node through a circuit-switched network coupled
intermediate to the first node and the serving node. The packet-switched
network may be a network employing, for example, the Internet Protocol
(IP), and the circuit-switched network may be the Public Switched
Telephone Network (PSTN), whereby calls originating from devices coupled
to the Internet, or similar network, can be directly routed to a serving
node of the wireless telecommunications network in communication with the
mobile device or, alternatively, through the PSTN. In a conventional
Public Land Mobile Network (PLMN), the first node of the wireless
telecommunications network can be a Gateway Mobile-Services Switching
Center (GMSC) and the serving node of the wireless telecommunications
network in communication with the mobile device can be a Mobile-Services
Switching Center (MSC).

Inventors:

VALENTINE, ERIC LEE; (PLANO, TX); BOLTZ, DAVID; (GARLAND, TX)

Correspondence Address:

ERICSSON INC.
6300 LEGACY DRIVE
M/S EVW2-C-2
PLANO
TX
75024
US

Serial No.:

217868

Series Code:

09

Filed:

December 21, 1998

Current U.S. Class:

370/352; 370/329

Class at Publication:

370/352; 370/329

International Class:

H04L 012/66

Claims

What is claimed is:

1. A method for routing information from a packet-switched network to a
mobile device communicating with a wireless telecommunications network,
said method comprising the steps of: receiving a call request for said
mobile device from said packet-switched network at a first node of said
wireless telecommunications network; determining a serving node of said
wireless telecommunications network in communication with said mobile
device; determining if said serving node is coupled to said
packet-switched network; and redirecting said call request to said
serving node in response to an affirmative indication that said serving
node is coupled to said packet-switched network.

2. The method recited in claim 1, further comprising the step of routing
said call request from said first node to said serving node through a
circuit-switched network coupled intermediate to said first node and said
serving node in response to a negative indication that said serving node
is coupled to said packet-switched network.

3. The method recited in claim 1, wherein said step of determining a
serving node of said wireless telecommunications network in communication
with said mobile device comprises the steps of: sending an inquiry to a
location resource of said wireless telecommunications network, said
inquiry including a unique identifier of said mobile device; querying a
database in said location resource using said unique identifier, said
database including an association between said unique identifier and said
serving node of said wireless telecommunications network in communication
with said mobile device.

4. The method recited in claim 3, wherein said inquiry includes an
indicator that said call request for said mobile device is from said
packet-switched network.

5. The method recited in claim 3, further comprising the step of sending a
request for routing information from said location resource to said
serving node of said wireless telecommunications network in communication
with said mobile device.

6. The method recited in claim 5, wherein said request for routing
information includes an indicator that said call request for said mobile
device is from said packet-switched network.

7. The method recited in claim 6, wherein said step of determining if said
serving node is coupled to said packet-switched network comprises the
step of transmitting a response to said request for routing information
from said serving node to said location resource, said response including
an address of said serving node on said packet-switched network.

8. The method recited in claim 5, wherein said step of determining if said
serving node is coupled to said packet-switched network comprises the
step of transmitting a response to said request for routing information
from said serving node to said location resource, said response including
a unique address of said serving node on said wireless telecommunications
network.

9. The method recited in claim 8, wherein said step of determining if said
serving node is coupled to said packet-switched network further comprises
the step of querying a database using said unique address of said serving
node on said wireless telecommunications network, said query returning an
address of said serving node on said packet-switched network in response
to said affirmative indication that said serving node is coupled to said
packet-switched network.

10. A system for routing information from a packet-switched network to a
mobile device communicating with a wireless telecommunications network,
said system comprising: means for receiving a call request for said
mobile device from said packet-switched network at a first node of said
wireless telecommunications network; means for determining a serving node
of said wireless telecommunications network in communication with said
mobile device; means for determining if said serving node is coupled to
said packet-switched network; and means for redirecting said call request
to said serving node in response to an affirmative indication that said
serving node is coupled to said packet-switched network.

11. The system recited in claim 10, further comprising means for routing
said call request from said first node to said serving node through a
circuit-switched network coupled intermediate to said first node and said
serving node in response to a negative indication that said serving node
is coupled to said packet-switched network.

12. The system recited in claim 10, wherein said means for determining a
serving node of said wireless telecommunications network in communication
with said mobile device comprises: means for sending an inquiry to a
location resource of said wireless telecommunications network, said
inquiry including a unique identifier of said mobile device; means for
querying a database in said location resource using said unique
identifier, said database including an association between said unique
identifier and said serving node of said wireless telecommunications
network in communication with said mobile device.

13. The system recited in claim 12, wherein said inquiry includes an
indicator that said call request for said mobile device is from said
packet-switched network.

14. The system recited in claim 12, further comprising means for sending a
request for routing information from said location resource of said
serving node of said wireless telecommunications network in communication
with said mobile device.

15. The system recited in claim 14, wherein said request for routing
information includes an indicator that said call request for said mobile
device is from said packet-switched network.

16. The system recited in claim 15, wherein said means for determining if
said serving node is coupled to said packet-switched network comprises
means for transmitting a response to said request for routing information
from said serving node to said location resource, said response including
an address of said serving node on said packet-switched network.

17. The system recited in claim 14, wherein said means for determining if
said serving node is coupled to said packet-switched network comprises
means for transmitting a response to said request for routing information
from said serving node to said location resource, said response including
a unique address of said serving node on said wireless telecommunications
network.

18. The system recited in claim 17, wherein said means for determining if
said serving node is coupled to said packet-switched network further
comprises means for querying a database using said unique address of said
serving node on said wireless telecommunications network, said query
returning an address of said serving node on said packet-switched network
in response to said affirmative indication that said serving node is
coupled to said packet-switched network.

19. An apparatus for controlling the routing of information from a
packet-switched network to a mobile device communicating with a wireless
telecommunications network, said apparatus comprising: means for
receiving a call request for said mobile device from said packet-switched
network at a first node of said wireless telecommunications network;
means for sending an inquiry to a location resource of said wireless
telecommunications network, said inquiry including a unique identifier of
said mobile device; means for receiving a response to said inquiry, said
response including a unique address of a serving node on said wireless
telecommunications network in communication with said mobile device;
means for querying a database using said unique address of said serving
node on said wireless telecommunications network, said query returning an
address of said serving node on said packet-switched network if said
serving node is coupled to said packet-switched network; and means for
redirecting said call request to said serving node in response to an
affirmative indication that said serving node is coupled to said
packet-switched network.

22. The apparatus recited in claim 21, wherein said address of said
serving node on said packet-switched network comprises an Internet
Protocol (IP) address.

22. The apparatus recited in claim 19, further comprising means for
routing said call request from said first node to said serving node
through a circuit-switched network coupled intermediate to said first
node and said serving node in response to a negative indication that said
serving node is coupled to said packet-switched network.

25. An apparatus for controlling the routing of information from a
packet-switched network to a mobile device communicating with a wireless
telecommunications network, said apparatus comprising: means for
receiving an inquiry from a first node of said wireless
telecommunications network, said inquiry including a unique identifier of
said mobile device and an indicator that a call request for said mobile
device is from said packet-switched network; means for querying a
database using said unique identifier of said mobile device, said
database including an association between said unique identifier and a
serving node of said wireless telecommunications network in communication
with said mobile device; means for sending a request for routing
information to said serving node of said wireless telecommunications
network in communication with said mobile device, said request for
routing information including an indicator that said call request for
said mobile device is from said packet-switched network; means for
receiving a response to said request for routing information from said
serving node, said response to said request including an address of said
serving node on said packet-switched network if said serving node is
coupled to said packet-switched network; and means for sending a response
to said inquiry to said first node of said wireless telecommunications
network, said response to said inquiry including said address of said
serving node on said packet-switched network if said serving node is
coupled to said packet-switched network.

26. The apparatus recited in claim 25, wherein said apparatus comprises a
Home Location Resource (HLR).

28. The apparatus recited in claim 27, wherein said address of said
serving node on said packet-switched network comprises an Internet
Protocol (IP) address.

29. The apparatus recited in claim 25, wherein said response to said
request for routing information from said serving node further includes
an address of said serving node on a circuit-switched network coupled
intermediate to said first node and said serving.

31. The apparatus recited in claim 25, wherein said first node of said
wireless telecommunications network comprises a Gateway Mobile-Services
Switching Center (GMSC).

32. The apparatus recited in claim 25, wherein said serving node of said
wireless telecommunications network in communication with said mobile
device comprises a Mobile-Services Switching Center (MSC).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention is directed, in general, to wireless
communications systems and, more specifically, to apparatus or methods to
route information from a packet-switched network to a mobile device
communicating with a wireless telecommunications network.

BACKGROUND OF THE INVENTION

[0002] The world is currently experiencing revolutionary changes in
communication systems, brought about by the general availability of
access to the Internet as well as wireless telephony. In particular,
interest in Internet Protocol (IP) telephony, or Voice over IP (VoIP),
has expanded rapidly as the associated technologies have matured.
Interoperability is a prominent factor in the success of Internet
telephony. The creation of the International Telecommunications Union
(ITU) Recommendation H.323 is one step to ensure such interoperability.

[0003] Recommendation H.323 describes the technical requirements for
multimedia communications services in a packet-switched network, such as
the communication of audio, video and data over the conventional
Internet. Packet-switched networks, however, may also include private and
public local area networks (LANs), wide-area networks (WANs), and
point-to-point dial-up connections over point-to-point protocol (PPP) or
other packet-switched protocols. The advent of IP telephony allowing
phone calls across packet-switched networks triggered a revolution in the
telecommunications industry. Early IP telephony, however, had many
limitations that prevented it from becoming a mainstream telephony
service. One of the biggest problems was a lack of connectivity between
an IP telephony network and the public switched telephone network (PSTN).
This led to the development of a gateway that allows IP and PSTN
customers to communicate with each other; such communications, however,
have conventionally required the routing of information between IP and
PSTN customers through the circuit-switched network of the PSTN.

[0004] The telecommunications industry has also recently undergone a
revolution in the area of wireless telephony; e.g., "cellular" or
"mobile" devices. Wireless telecommunications networks are an adjunct to
the PSTN, and depend upon the circuit-switched network of the PSTN for
communications with conventional wired telephony devices as well as with
mobile devices. Thus, the routing of information to a mobile device
communicating with a wireless telecommunications network has heretofore
also required all such information to be routed through the PSTN.

[0005] Because of the proliferation of IP telephony and mobile devices,
there is a need in the art for apparatus, methods and systems for
efficiently routing information from a packet-switched network to a
mobile device communicating with a wireless telecommunications network.
Because both IP telephony and mobile devices currently depend upon the
circuit-switched network of the PSTN, even greater demand will be placed
on the PSTN as IP telephony and mobile device capabilities and services
continue to expand. Accordingly, there is a particular need in the art
for apparatus, methods and systems for routing information between IP
telephony and mobile devices that do not require use of the
circuit-switched network of the PSTN.

SUMMARY OF THE INVENTION

[0006] To address the above-discussed deficiencies of the prior art, the
present invention relates to apparatus, methods and systems for routing
information from a packet-switched network to a mobile device
communicating with a wireless telecommunications network. In one
embodiment of a wireless telecommunications system employing the
principles of the invention, a call request for a mobile device is
received from the packet-switched network at a first node of the wireless
telecommunications network; a determination is made of the serving node
of the wireless telecommunications network in communication with the
mobile device and whether the serving node is coupled to the
packet-switched network; and the call request is redirected to the
serving node in response to an affirmative indication that the serving
node is coupled to the packet-switched network. Alternatively, if the
serving node is not coupled to the packet-switched network, the call
request is routed from the first node to the serving node through a
circuit-switched network coupled intermediate to the first node and the
serving node.

[0007] In various embodiments, the determination of the serving node of
the wireless telecommunications network in communication with the mobile
device is accomplished by (i) sending an inquiry to a location resource
of the wireless telecommunications network, wherein the inquiry includes
a unique identifier of the mobile device, such as the Mobile Station
Integrated Service Digital Network (MSISDN) number identifying the mobile
subscriber or device; and (ii) querying a database in the location
resource using the unique identifier, wherein the database includes an
association between the unique identifier and the serving node of the
wireless telecommunications network in communication with the mobile
device.

[0008] Once the serving node of the wireless communications network in
communication with the mobile device has been identified, it is then
determined whether that serving node is coupled to the packet-switched
network. In one embodiment, the inquiry sent to the location resource
includes an indicator that the call request for the mobile device is from
the packet-switched network. The location resource then sends a request
for routing information to the serving node of the wireless
telecommunications network in communication with the mobile device; the
request for routing information includes an indicator that the call
request for the mobile device is from the packet-switched network. The
serving node then transmits a response to the request for routing
information to the location source; the response includes the unique
address of the serving node on the wireless telecommunications network.
The response also includes an address of the serving node on the
packet-switched network if it is coupled to that network. If the serving
node is coupled to the packet-switched network, the call request is
redirected to the serving node. Alternatively, if the serving node is not
coupled to the packet-switched network, the call request is routed from
the first node to the serving node through the circuit-switched network
coupled intermediate to the first node and the serving node.

[0009] In an alternate embodiment, conventional signaling can be employed
between the first node, location resource and serving node to return the
unique address of the serving node on the wireless telecommunications
network to the first node. The determination of whether the serving node
is coupled to the packet-switched network is then accomplished by
querying a database using the unique address of the serving node on the
wireless telecommunications network; the query returns an address of the
serving node on the packet-switched network if the database identifies
that the serving node is coupled to the packet-switched network. If the
serving node is coupled to the packet-switched network, the call request
is redirected to the address of the serving node on the packet-switched
network. Alternatively, if the serving node is not coupled to the
packet-switched network, the call request is routed from the first node
to the serving node through the circuit-switched network coupled
intermediate to the first node and the serving node.

[0010] The principles of the present invention may be employed to
advantage in combinations of various packet-switched and wireless
communication network topologies. The packet-switched network may be, for
example, the Internet and the circuit-switched network may be the Public
Switched Telephone Network (PSTN), whereby calls originating from devices
coupled to the Internet, or similar network, can be directly routed to a
serving node of the wireless telecommunications network in communication
with the mobile device or, if the serving node is not coupled to the
Internet, such calls can be routed through the PSTN. If the
packet-switched network is the Internet, the address of the serving node
is preferably an Internet Protocol (IP) address; as used herein, "IP
address" is defined to include a basic IP address, a "socket," which
comprises an IP address plus a port number, and an IP address plus any
other data used to identify a transaction or process associated with the
IP address. If the present invention is employed in a conventional Public
Land Mobile Network (PLMN), the first node of the wireless
telecommunications network can be a Gateway Mobile-Services Switching
Center (GMSC), the serving node of the wireless telecommunications
network in communication with the mobile device can be a Mobile-Services
Switching Center (MSC), and the location resource can be a Home Location
Register (HLR). Those skilled in the art will readily conceive of other
packet-switched and wireless communication network topologies that may
advantageously employ the principles of the invention; such applications
of the invention are intended to be within the scope of the claims
recited hereinafter.

[0011] As described more fully hereinafter, the present invention provides
various apparatus, methods and systems for routing information from a
packet-switched network to a mobile device communicating with a wireless
telecommunications network. Instead of always routing such information
through a circuit-switched network associated with the wireless
telecommunications network, the present invention redirects a call
request for a mobile device to the serving node of the wireless
communications network in communication with the mobile device if the
serving node is coupled to the packet-switched network, thereby bypassing
the circuit-switched network.

[0012] The foregoing has outlined, rather broadly, the principles of the
present invention so that those skilled in the art may better understand
the detailed description of the exemplary embodiments that follow. Those
skilled in the art should appreciate that they can readily use the
disclosed conception and exemplary embodiments as a basis for designing
of modifying other structures and methods for carrying out the same
purposes of the present invention. Those skilled in the art should also
realize that such equivalent constructions do not depart from the spirit
and scope of the invention in its broadest form, as delimited by the
claims recited hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a more complete understanding of the present invention,
reference is now made to the following detailed description taken in
conjunction with the accompanying drawings, in which:

[0014] FIG. 1 illustrates a simplified diagram of a prior art system for
routing information from a packet-switched network to a mobile device
communicating with a wireless telecommunications network;

[0015] FIG. 2 illustrates a simplified diagram of a first exemplary system
for routing information from a packet-switched network to a mobile device
communicating with a wireless telecommunications network in accordance
with the principles of the present invention;

[0016] FIG. 3 illustrates a simplified diagram of a second exemplary
system for routing information from a packet-switched network to a mobile
device communicating with a wireless telecommunications network in
accordance with the principles of the present invention;

[0017] FIG. 4 illustrates an exemplary flow diagram of a method for
routing information from a packet-switched network to a mobile device
communicating with a wireless telecommunications network in accordance
with the principles of the present invention;

[0018] FIG. 5-A illustrates a first exemplary method for determining
whether a serving node of a wireless telecommunications network in
communication with a mobile device is coupled to a packet-switched
network; and

[0019] FIG. 5-B illustrates a second exemplary method for determining
whether a serving node of a wireless telecommunications network in
communication with a mobile device is coupled to a packet-switched
network.

DETAILED DESCRIPTION

[0020] Referring to FIG. 1, illustrated is a simplified diagram of a prior
art system 100 for routing information from a packet-switched network 110
to a mobile device 120 communicating with a wireless telecommunications
network 130. The wireless telecommunications network 130, or Public Land
Mobile Network (PLMN), conventionally includes a Gateway Mobile-Services
Switching Center (GMSC) 131, at least one Mobile-Services Switching
Center (MSC) 132 coupled to the GMSC through the Public Switched
Telephone Network 140, at least one Base Station Subsystem (BSS) 133
coupled to each MSC 132, and a Home Location Resource (HLR), 134.

[0021] A packet-switched network 110, such as the Internet, is coupled to
a first node, e.g., GMSC 131, of the wireless telecommunications network
130 through an access server 111. A terminal device 150, such as a
personal computer having telephony capabilities, is coupled to a server
112, such as a conventional server of an Internet Service Provider (ISP),
on the packet-switched network 110. A call request directed to a mobile
device 120 from a terminal device 150 is routed through the
packet-switched network 110 from the server 112 to the access server 111,
which then transmits the call request to the GMSC 131; the call request
includes a unique identifier of the mobile device 120, such as the Mobile
Station Integrated Service Digital Network (MSISDN). Typically,
communication of a payload (e.g., voice) between the access server 111
and GMSC 131 generally conform to the ITU G.711 (PCM) standard, and
signaling conforms, for example, to the ISUP or Q.931 standards; thus,
the packet-switched, e.g., Internet Protocol (IP), segment of the call
request terminates at the GMSC 131. The GMSC 131 then sends an inquiry,
e.g., Send_Routing_Information, to a location resource, e.g., HLR 134, to
determine the location of the mobile device 120 having the unique
identifier. The HLR 134 queries a database using the unique identifier,
wherein the database includes an association between the unique
identifier and the serving node, e.g., MSC 132, of the wireless
telecommunications network 130 in communication with the mobile device
120. The HLR 134 then sends a request, e.g., Provide_Routing_Number, the
MSC 132 to obtain a routing number, e.g., a Mobile Subscriber Routing
Number (MSRN), for the mobile device 120. The MSC 132 responds to the
Provide_Routing_Number request by sending the MSRN to the HLR 134, which
then sends the MSRN back to the GMSC 131. The GMSC 131 then uses the MSRN
to route the call request to the MSC 132 through the PSTN 140, and the
MSC 132 completes the call to the mobile device 120 through the proper
BSS 133 in communication with the mobile device 120.

[0022] Thus, the conventional method for routing call requests, such as
H.323 calls, from a packet-switched network, such as the Internet, to a
mobile device 120 terminates the packet-switched, or IP, segment of the
request at the first node, e.g., GMSC 131, of the wireless
telecommunications network 130. The remainder of the connection, from the
GMSC 131 to the MSC 132, is carried over a circuit-switched network, such
as the PSTN 140. This is not an efficient use of network resources
because only a negligible quality loss would be incurred by taking the IP
traffic all the way to the MSC 132. In addition, because the routing of
calls through the PSTN 140 is typically charged to the operator of the
wireless telecommunications network 130 or the subscriber of the mobile
device 120, the conventional method results in extra transmission
expenses either for the operator or subscriber.

[0023] Referring now to FIG. 2, illustrated is a simplified diagram of a
first exemplary system 200 for routing information from a packet-switched
network 110 to a mobile device 120 communicating with a wireless
telecommunications network 230 in accordance with the principles of the
present invention. According to the principles of the invention, call
requests from the packet-switched network 110 can be redirected to a
serving node having capability to receive packet-switched data, e.g., MSC
232 with IP capability, thereby bypassing the circuit-switched network,
e.g., PSTN 140, and thus overcoming the disadvantages of the prior art
method of routing such call requests. Those skilled in the art are
familiar with means for providing communications between an MSC and an IP
network and, thus, a detailed description of such means is unnecessary to
an understanding of the present invention.

[0024] In the first exemplary system 200, the MSC 232 is provided with the
capability to receive call requests from the packet-switched network 110.
This can be accomplished by providing the MSC 232 with the capability to
receive packet-switched, e.g., IP, traffic. In other words, call requests
can be redirected from the packet-switched network 110 to an MSC 232
having IP capability, either by providing a link between an access server
in the packet-switched network 110 and the MSC 232 or by locating an
access server of the packet-switched network 110 directly in the MSC 232.
Because the wireless telecommunications network 230 typically has many
MSCs through which the mobile device 120 may be reached, the MSC serving
the mobile device 120 at the time of the call request, and whether that
MSC has IP capability, must be determined before a call request can be
properly redirected.

[0025] In the first exemplary system 200, a call request directed to a
mobile 120 from a terminal device 150 is routed through the
packet-switched network 110 from the server 112 to the access server 211,
which then transmits the call request to the GMSC 231; the call request
includes a unique identifier of the mobile device 120, such as the Mobile
Station Integrated Service Digital Network (MSISDN). The GMSC 231 then
sends an inquiry, including an indication that the call request is from
the packet-switched network 110, to a location resource, e.g., HLR 234,
to determine the location of the mobile device 120 having the unique
identifier; the inquiry may, for example, be of the form
Send_Routing_Information (VoIP). The HLR 234 queries a database using the
unique identifier, wherein the database includes an association between
the unique identifier and the serving node, e.g., MSC 232, of the
wireless telecommunications network 130 in communication with the mobile
device 120. Once the serving node, e.g., MSC 232, of the wireless
communications network 230 in communication with the mobile device 120
has been identified, it is then determined whether that MSC is coupled to
the packet-switched network 110.

[0026] The HLR 234 sends a request including the VoIP indicator,
Provide_Routing_Number (VoIP), to an MSC to obtain a routing number,
e.g., a Mobile Subscriber Routing Number (MSRN), for the mobile device
120. An MSC responds to a Provide_Routing_Number (VoIP) request by
sending a MSRN to the HLR 234, which then sends the MSRN back to the GMSC
231. In addition, if the MSC receiving the Provide_Routing_Number (VoIP)
request has IP capability, such as MSC 232, the MSC also includes an
address, e.g., and IP address, of the MSC on the packet-switched network
110 in the response (MSRN+IP). The HLR 234 then sends the MSRN, and IP
address if available, to the GMSC 231. If no IP address for the serving
MSC is received by the GMSC 231, the GMSC 231 uses the MSRN to route the
call request to the MSC through the PSTN 140. If an IP address for the
serving MSC is received by the GMSC 231, however, the IP address is
provided to the access server 211, which then redirects the call request
to the MSC 232. Those skilled in the art are familiar with means for
redirecting data packets on a packet-switched network; for example, a
control message can be sent to the access server 211 with a command to
redirect all packets associated with the call to an IP address, or a
socket, associated with the MSC 232. The MSC 232 completes the call to
the mobile device 120 through the proper BSS 133 in communication with
the mobile device 120.

[0027] Referring now to FIG. 3, illustrated is a simplified diagram of a
second exemplary system 300 for routing information from a
packet-switched network 110 to a mobile device 120 communicating with a
wireless telecommunications network 330 in accordance with the principles
of the present invention. In this embodiment, conventional signaling can
be employed between the first node (e.g., GMSC 331), the location
resource (e.g., HLR 134) and the serving node (e.g., MSC 332) to return
the unique address of the MSC 332 on the wireless telecommunications
network 130 to the GMSC 331; identification can be accomplished by
examining the MSRN which, because it is a routable number, uniquely
identifies the serving MSC. The determination of whether the MSC is
coupled to the packet-switched network 110 is then accomplished by
querying a database using the unique address of the MSC on the wireless
telecommunications network 330; if the database identifies that the MSC
is coupled to the packet-switched network, the query returns a packet
routing address, e.g., an IP address, of the MSC on the packet-switched
network 110. If the MSC is coupled to the packet-switched network 110,
the call request is redirected to the address of the MSC 332 on the
packet-switched network 110. Alternatively, if the MSC is not coupled to
the packet-switched network 110, the call request is routed from the GMSC
331 to the MSC through the PSTN 140.

[0028] In the second exemplary system 300, a call request directed to a
mobile device 120 from a terminal device 150 is routed through the
packet-switched network 110 from the server 112 to the access server 311,
which then transmits the call request to the GMSC 331; the call request
includes a unique identifier of the mobile device 120, such as the Mobile
Station Integrated Service Digital Network (MSISDN). The GMSC 331 then
sends an inquiry, Send_Routing_Information, to a location resource, e.g.,
HLR 134, to determine the location of the mobile device 120 having the
unique identifier. The HLR 134 queries a database using the unique
identifier, wherein the database includes an association between the
unique identifier and the serving node, e.g., MSC 332, of the wireless
telecommunications network 330 in communication with the mobile device
120. The HLR 134 sends a request, Provide_Routing_Number, to the MSC 332
to obtain a routing number, e.g., a Mobile Subscriber Routing Number
(MSRN), for the mobile device 120. An MSC responds to a
Provide_Routing_Number request by sending a MSRN to the HLR 134, which
then sends the MSRN back to the GMSC 331, whereby the serving node, e.g.,
MSC 332, of the wireless communications network 330 in communication with
the mobile device 120 is identified to the GMSC 331. It is then
determined whether that MSC is coupled to the packet-switched network
110.

[0029] The determination of whether the MSC is coupled to the
packet-switched network 110 is accomplished by querying a database 335
using the unique address of the MSC on the wireless telecommunications
network 330; the database 335 comprises tables that associate the unique
addresses of the MSCs on the wireless telecommunications network 330 with
addresses on the packet-switched network 110. The query returns an
address of the MSC on the packet-switched network 110 if the database 335
identifies that the MSC is coupled to the packet-switched network 110. If
the MSC is coupled to the packet-switched network 110, the call request
is redirected to the address of the MSC 332 on the packet-switched
network 110. Alternatively, if the MSC is not coupled to the
packet-switched network 110, the IP address for the MSC is provided to
the access server 211, which then redirects the call request to the MSC
332. The MSC 332 completes the call to the mobile device 120 through the
proper BSS 133 in communication with the mobile device 120.

[0030] Turning now to FIG. 4, illustrated is an exemplary flow diagram of
a method 400 for routing information from a packet-switched network to a
mobile device communicating with a wireless telecommunications network in
accordance with the principles of the present invention. In a first step
410, a first node of the wireless telecommunications network, e.g., a
GMSC, receives a call request for a mobile device. In a step 420, it is
determined whether the call request is from a device coupled to a
packet-switched network, e.g., an IP network. If the call request is not
from a packet-switched network, the call is routed to the mobile device
via a circuit-switched network, such as the PSTN, in a step 430. If the
call request is from a packet-switched network, however, the serving
node, e.g., an MSC, of the wireless telecommunications network in
communication with the mobile device, and whether the MSC has IP
capability, is determined in a step 440; alternative methods of making
these determinations are described hereinafter with reference to FIGS.
5-A and 5-B. If the MSC in communication with the mobile device does not
have IP capability, the call is routed to the mobile device via a
circuit-switched network, such as the PSTN, in a step 430. If the MSC
does have IP capability, however, the IP address of the MSC is provided
to a routing device of the packet-switched network in a step 460, and the
call request is then redirected to the IP address of the MSC via the
packet-switched network in a step 470.

[0031] Referring now to FIG. 5-A, illustrated is a first exemplary method
540-A for determining whether a serving node of a wireless
telecommunications network in communication with a mobile device is
coupled to a packet-switched network; the first exemplary method 540-A
corresponds to, and is preferably employed in, the first exemplary system
200 illustrated in FIG. 2. In a step 541-A, a first node, e.g., a GMSC,
of the wireless telecommunications network sends an inquiry, e.g.,
Send_Routing_Information (VoIP), to a locations resource, e.g., an HLR,
associated with the wireless telecommunications network; the inquiry
includes a unique address of the mobile device, such as a MSISDN, and an
indicator that the call request is from a packet-switched network, e.g.,
a voice over IP (VoIP) call. In a step 542-A, the HLR queries a database
to determine the MSC in communication with the mobile device and then
sends a request for a routing number, Provide_Routing_Number (VoIP), that
includes an indicator that the call request is from the packet-switched
network to that MSC. If the MSC does not have an address on the
packet-switched network, the MSC returns only the routing number, which
uniquely identifies the MSC in communication with the mobile device to
the GMSC in a step 544-A, the routing number can be returned to the GMSC
via the HLR. If the MSC does have an address on the packet-switched
network, e.g., an IP address, the MSC returns the IP address to the GMSC
in a step 545-A; in addition, the MSC can also return the routing number
to the GMSC to alternatively allow routing of the call request through
the PSTN.

[0032] Finally, FIG. 5-B, illustrated is a second exemplary method 540-B
for determining whether a serving node of a wireless telecommunications
network in communication with a mobile device is coupled to a
packet-switched network; the second exemplary method 540-A corresponds
to, and is preferably employed in, the second exemplary system 300
illustrated in FIG. 3. In a step 541-B, a first node, e.g., a GMSC, of
the wireless telecommunications network sends and inquiry, e.g.,
Send_Routing_Information, to a location resource, e.g., an HLR,
associated with the wireless telecommunications network; the inquiry
includes a unique address of the mobile device, such as a MSISDN. In a
step 542-B, the HLR queries a database to determine the MSC in
communication with the mobile device and then sends a request,
Provide_Routing_Number, for a routing number to the mobile device through
that MSC. In a step 543-B, the MSC returns the routing number, which
uniquely identifies the MSC in communication with the mobile device, to
the GMSC; the routing number can be returned to the GMSC via the HLR. In
a step 544-B, the GMSC then queries a database, using the routing number
as a pointer into the database, to determine whether the MSC identified
by the routing number is coupled to the packet-switched network (e.g.,
whether the MSC has an IP address reachable through the packet-switched
network).

[0033] The present invention provides significant advantages to wireless
communications systems, in general, and the invention is particularly
advantageous in wireless communications networks coupled to a
packet-switched network, such as the Internet. The principles of the
apparatus, methods and systems for routing information from a
packet-switched network to a mobile device communicating with a wireless
telecommunications network disclosed herein can optimize the routing of
call requests from packet-switched networks to mobile devices, while
decreasing the utilization of circuit-switched network resources, such as
the PSTN.

[0034] Although the present invention has been described in detail, those
skilled in the art will conceive of various changes, substitutions and
alterations to the exemplary embodiments described herein without
departing from the spirit and scope of the invention in its broadest
form. The exemplary embodiments presented herein illustrate the
principles of the invention and are not intended to be exhaustive or to
limit the invention to the form disclosed; it is intended that the scope
of the invention be defined by the claims appended hereto, and their
equivalents.